Heretofore, an external preparation for skin for anti-aging consisting of a polymerization product with an average molecular weight of 280-20000 of a tripeptide composed of one glycine residue and two other amino acid residues in a degradation product of collagen or gelatin by collagenase (see Patent Document 1), a collagen-production promoter comprising a mixture of tripeptides (Gly-Ala-Arg), (Gly-Ala-Hyp), (Gly-Ala-Lys), (Gly-Pro-Ala), (Gly-Pro-Arg), (Gly-Pro-Hyp), and (Gly-Pro-Ser) as an active ingredient (see Patent Document 2) and others are known as physiologically active substances comprising an oligopeptide or a polymerization product thereof as an active ingredient.
Alternatively, an oral hair growth promoting agent comprising, as an active ingredient, a peptide represented by R1-Met-Ile-XR2 (wherein X represents Trp, Phe, Trp-Leu, Phe-Leu, Tyr-Leu, Ile-Leu, or Leu-Leu; R1 represents a hydrogen atom or an amino-protecting group; and R2 represents a hydroxyl- or carboxyl-protecting group) or a pharmacologically acceptable salt thereof is known as a special substance (see Patent Document 3).
A variety of physiologically active substances comprising a peptide as an active ingredient is known, as described above. However, a UV-induced dermatitis inhibitor and an atopic dermatitis inhibitor comprising a peptide as an active ingredient are unknown.
Patent Document 1: Japanese Patent Laid-Open No. 2000-309521
Patent Document 2: Japanese Patent Laid-Open No. 2003-137807
Patent Document 3: Pamphlet of International Publication No. WO 00/29425